by Natasha Erdman, Ph.D., Product Manager, JEOL USA
The advent of new technologies and materials with specific properties designed and manifested at the sub-micron scale has ushered in an increased need to equip characterization labs with innovative -- yet compact -- scanning electron microscopy (SEM) and microanalysis (EDS or XRF) setups. The purpose of such a resource is to provide, in most cases, an easy-to-use platform that will serve as an initial step in materials characterization workflow. This SEM/EDS resource will perform full characterization of a specimen, requiring a high level of performance in terms of resolution, complimentary analytical detectors, and software for comprehensive analysis.
Photo: EDS map - pharma API for drug delivery. Credit: JEOL
Scanning electron microscopes are considered to be one of the most versatile and powerful tools for scientists because of their large depth of field (in comparison to optical microscopes), great spatial resolution (high magnification), and the capacity for chemical composition analysis via several types of spectroscopy. Visualization of specimen topography, microstructure, or establishing the cause of failure is achieved easily through a single image in some cases. Yet, it is often necessary to set up a multidimensional approach to be able to answer questions about material properties that will steer future technological progress.
In such cases SEM provides unparalleled flexibility through the addition of an assortment of electrical, mechanical, and chemical test equipment making the instrument a self-contained “nano-laboratory.” Integrated tabletop SEM workflows, such as those offered by JEOL, enable new and more flexible approaches to the analysis of various types of materials, such as semiconductors, powders for additive manufacturing, and polymers, as well as unique approaches to 3D analysis in SEM.
From Macro to Nano – Enhanced Navigation and Cross-Referencing
One of the requirements vital to researchers is the ability to connect microstructural defects or features to its micro and nanostructural properties. This could be key to understanding and improving upon the current material design. Some SEM systems enable the user to take a snapshot of the specimen (an optical image) prior to SEM observation, and then maneuver to a region of interest based on this image.
With this feature available, the user can magnify the area to the requisite feature size and observe and chemically analyze the location with the SEM while retaining the optical image tag. This is remarkably useful for the observation of multiple specimens or multiple locations on the same specimen.
Real-time, Embedded Chemical Analysis with SEM
Tabletop SEMs can come with fully embedded and integrated Energy Dispersive X-Ray Spectroscopy (EDS) systems that can tag specific locations with chemical analysis and offer real-time compositional data (point analysis or mapping) and spatial distribution of components at the micro and nanometer scale as the multiple samples or locations on the specimen are scanned.
Particle and Fiber Analysis
SEM is well suited to perform particle and fiber analysis by providing a high-resolution view of the sample’s surface morphology and details on sizes and shapes. Integrated EDS further allows the SEM to classify particles by their chemical type. To streamline this process, automation workflows are available for fast throughput and unattended operation. This enhances existing inspection capabilities in areas like automotive cleanliness, additive manufacturing, pharma, and energy.
3D Analysis of Surfaces
Photo: Live 3D surface morphology of star-shaped beach sand during SEM observation using a multi-segmented backscatter detector. Credit: JEOL
Long depth of field related to SEM imaging has conventionally appealed to researchers because of the fundamental ability to generate a more three-dimensional representation of the specimen surface in contrast to optical microscopy. There has been a concerted effort recently to take this capability even further, with various software and hardware solutions that provide not only qualitative but also a quantitative representation of the 3D nature of specimen surfaces.
The proposed solutions range from simple composites of two or more stereo pair images (easily acquired through tilt series) to the actual redesign of detectors to obtain several images synchronously and merge those images to create a live 3D representation of the specimen surface that can be easily tilted, rotated, and manipulated by the user.
Additional Workflow Components - Sample Preparation
SEM analysis integrity always relies on suitable sample preparation, which is an integral part of an efficient tabletop workflow. A compact, automated sputter coater makes it easy to quickly and consistently coat non-conductive specimens with either a metal or carbon coating layer prior to imaging. A tabletop broad ion beam specimen preparation device prepares pristine cross-sections of any type of material. Some preparative devices allow users to utilize cryogenic and air isolated transfer mechanisms for preparation of temperature and environment sensitive materials.
Multidimensional tabletop workflow solutions allow researchers to set up a compact and user-friendly lab environment for SEM. This technology seamlessly guides the user from sample preparation to imaging, microanalysis and reporting.
About the Author: Natasha Erdman, Ph.D. joined JEOL USA in 2004 as Product Manager for SEM/Ion beam products to provide technical support for sales and marketing and to find the best microscopy and sample preparation solutions for customers. She managed day to day operations in the SEM products demo lab, working with our in-house scientists to identify new or more efficient workflows to answer scientific questions from a variety of industries and academic labs. She has co-authored multiple articles, book chapters and a book on low voltage electron microscopy. She holds a Ph.D. in Materials Science from Northwestern University, and recently was appointed Product Marketing Manager for all JEOL USA electron microscopy products.